However, EE adds: “We aim to cover as much of the 10 cities as we can, but just so you know, all postcodes may not be switched on at the same time”.

By the end of 2012, EE aims to have an additional six cities smothered in 4G, bringing coverage to at least one third of the population. The subsequent six are Belfast, Derby, Hull, Nottingham, Newcastle and Southampton.

I'm leaving o2 to go to t-mobile. I'd decided this months ago and was going to go for one of their sim only tariffs. The Lumia 920 changed my mind about sim only.
I'll probably make the move to a 4G tariff if the price is right maybe a few months after it becomes available in my city.